JPH0345653A - Amorphous blend which contains at least amorphous semiaromatic polyamide derived from alkylpentamethylenediamineand aromatic dicarboxylic acid, and nylon-type semicrystalline polyamide derived from hexamethylenediamine, adipic acid and/or epsilon-caprolactam, and manufacture of said blend - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a single-phase and amorphous polymer blend which can be used in particular to produce articles shaped by molding; of an amorphous semi-aromatic polyamide derived from at least one alkylpentamethylene diamine and an aromatic dicarboxylic acid, on the other hand a small amount of hexamethylene diamine, adipic acid and/or ε-caprolactam. and a semi-crystalline polyamide of the nylon type. The invention also relates to methods of making these blends.

[Prior Art and Problems to be Solved by the Invention] High molecular weight, exclusively aliphatic, linear polyamides of the nylon type are fabricated into a variety of molded articles such as fibers, films and other molded articles. It has many physical and chemical properties that make it suitable for use.

For example, polyhexamethylene cyacivamide or nylon 66 is a polyamide that has been very widely developed. However, these polymers exhibit a number of drawbacks, the importance of which is related to the intended application. In many cases,
These polyamides are semi-crystalline polymers and are therefore not transparent (and they cannot be used in fields of applications where transparency is required; furthermore, these polyamides have a non-trivial Shrinkage due to molding, non-negligible water uptake and, as a result, dimensional stability against moisture that may be insufficient as well as mechanical properties that are affected by ambient moisture and deteriorate at temperatures above 100°C. (Insufficient height of glass transition temperature Tg,
generally below 80°C).

A large number of patents describe polyamides with various groups, such as certain polyamides containing a mixture of aliphatic and aromatic units, which may ameliorate all or some of the above disadvantages. I can do it. The introduction of aromatic rings is accompanied by an increase in the melting or softening point or Tg, resulting in better retention of mechanical properties, especially at high temperatures. Furthermore, when employed in their compositions, these polyamides can be amorphous polymers. Typical amorphous semi-aromatic polyamides include, for example, hexamethylene diamine as well as isophthal (60-90 mol % in the diacid mixture).
and terephthalic acid (U.S. Pat. No. 3,382)
．． 216) and obtained from 2-methylbentamethylene diamine and isophthalic acid (15 to 30 mol % in the diacid mixture) and terephthalic acid (French patent no. 32
No. 5,673) may be mentioned. However, due to the high melt viscosity, the melting process of these amorphous semi-aromatic polyamides,
Conversions by injection, for example, require high processing temperatures which tend to retard their development, which are, for example, in the case of the above-mentioned copolymers obtained from hexamethylene diamine and aromatic acids, of the order of 280°C to 300°C; - In the case of the above-mentioned copolymers obtained from methylpentamethylene diamine and aromatic acids, the temperature is about 290 DEG C. to 310 DEG C. Furthermore, semi-aromatic polyamides exhibit very low shrinkage, which often makes demolding of molded articles made with these materials difficult.

As research continues in the field of semi-aromatic polyamides, it is hoped that we will have useful polyamides that exhibit a combination of at least the following properties.

- Can be used in areas of application where good transparency is required: - Good polymer stability and better mechanical properties at high temperatures than occur when starting from polyamides of the nylon type. have a Tg higher than 100°C in order to be able to produce molded articles, for example by injection, that can exhibit maintenance; melting in the mode of moderate processing temperatures, temperatures in the range 270°C to 290°C; The melt viscosity is lower than that of semi-aromatic polyamides, so that it can be easily converted by the process; Moderate, slight molding shrinkage, the extent of which To provide a degree of shrinkage greater than that obtained in the case of semi-aromatic polyamides, but less than that obtained in the case of nylon-type polyamides.

Claims (9)

[Claims] (1) A single phase, amorphous blend comprising an amorphous semi-aromatic polyamide and a nylon-type semi-crystalline polyamide, the amount of the nylon-type semi-crystalline polyamide in the blend of the two types of polyamides. (i) the starting amorphous semi-aromatic polyamide can be a homo- or copolymer, and has the following characteristics: The polyamide has the following formulas (I), (II), (III) and ( The structure contains repeating units of IV); (I): Those that show the following structure ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II): Those that show the following structure ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III ): Something that shows the following structure ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IV): Something that shows the following structure ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Formula (II) and formula (IV) are arbitrary. Unit (I) for the sum of unit (III) + any (IV)
+ the molar ratio of any unit (II) is equal to 1, (I) +
The amount of units (II) in the mixture of (II) is in the range from 0 to 15 mol%, and the amount of units (I) is (I)+(II)
The amount of unit (IV) in the mixture (III) + (IV) is in the range of 0 to 90 mol%.
mol % and the amount of units (III) in the mixture (III) + (IV) is from 100 to 10
(ii) Semi-crystalline polyamides of the nylon type can be homo- or copolymers, including nylon 66 (a polymer of hexamethylene diamine and adipic acid), nylon 6 (a polymer of hexamethylene diamine and adipic acid),
(iii) the amount of semi-crystalline polyamide (ii) is A blend as described above, characterized in that it represents less than 40% of the total weight of aromatic polyamide (i) + semicrystalline polyamide (ii). (2) Amorphous semi-aromatic polyamide (i), on the other hand, has an amount of units (II) in the mixture (I) + (II) of 0 to 5
in the range of mol %, the amount of units (I) in the mixture (I)
+ (II), the amount of unit (IV) is in the range of 100 to 95 mol %, and in the mixture (III) + (IV), the amount of unit (IV) is 0 to 85 mol %
and the amount of units (III) in the mixture (III)
+(IV) exhibits a structure corresponding to the above definition in the range of 100 to 15 mol %, and on the other hand has viscosity properties of ISO standard R307 (1
Meta-cresol 100c according to 984, 2nd edition)
m^3 to at least 90 ml/g, expressed in the form of the viscosity index (VI) in meta-cresol at 25° C. as a solution containing 0.5 g of polymer (dried for 2 hours at 60° C. under a purge of argon) in 2. The blend of claim 1 showing equality. (3) an amorphous semi-aromatic polyad, on the one hand, in the mixture (III) + (IV), the amount of units (IV) is in the range 60-85 mol %, and the amount of units (III) shows the structure corresponding to the above in the range of 40 to 15 mol % in the mixture (III) + (IV), and on the other hand the VI value is 100 ml/g to 150 ml/g.
The blend of claim 2 exhibiting g. (4) A semi-crystalline polyamide of the nylon type is expressed in the form of a viscosity index (VI) in terms of the part soluble in acid with a purity of 90% by weight according to ISO standard R307 (1984, 2nd edition), Blend according to any one of claims 1 to 3 exhibiting viscosity properties at least equal to 120 ml/g. (5) 130ml of nylon-type semi-crystalline polyamide
5. The blend of claim 4 comprising nylon 66 (a polymer of hexamethylene diamine and adipic acid) exhibiting a viscosity index (VI) value of between 180 ml/g and 180 ml/g. (6) A blend according to claims 1 to 5, wherein the amount of semi-crystalline polyamide (ii) represents from 10 to 40% of the total weight of semi-aromatic polyamide (i) + semi-crystalline polyamide (ii). (7) The amount of semi-crystalline polyamide (ii) is 20% by weight
7. The blend of claim 6 in the range of ~35%. (8) A method for producing a blend according to any one of claims 1 to 7, comprising a first step of stirring the constituents together at room temperature in a conventional high speed mixer for powders or particles; two steps, with a second step in which the mixture is homogenized by blending in the molten phase at a temperature ranging from 270° C. to 290° C. and the operation is carried out in an apparatus that allows blending of the plastics in the molten state; A method for producing the above blend, which is carried out by carrying out. (9) A molded article obtained from the blend according to any one of claims 1 to 6.